Cooling pad



April 11, 1939. M. A SAVAGE COOLING PAD Filed June 24. 1936 e, e5 wv n0% r mbv@ GA/LW Vn A www 4 r s MQWH U4 9 Ilf Patented Apr. 11, 1939UNITED STATES COOLING PAD Marion A. Savage, Scotia, N. Y., assignor toGeneral Electric Company, a corporation of New York Application June 24,193e, serial No. 86,966

2 Claims.

My invention relates to cooling pads which are primarily adapted forinsertion between bundles of laminations in dynamo-electric machine corestructures for removing heat therefrom. These cooling pads havesubstantially parallel flat face portions which make contact with thebundles of laminations and transfer the heat from the laminations to acooling fluid circulated through the pad.

m Itis an object of my invention to provide a pad of improvedconstruction.

It is a further object of my invention to provide a pad in which theparts thereof are formed of metal sheets and strips integrally attachedto one another to form a unitary structure.

` embodying the structural features thereof; Figs.

2 `to 6 inclusive, are views illustrating the procedure by means ofwhich this pad is fabricated; Fig. 7 is a pla'n view of the interiorarrangement i of the partition and reinforcing strips attached to theinner surface of one of the sheets forming the pad; and Fig. 8 is across section of the body portion of the pad shown in Fig. 1. Fig. 2illustrates the two flat sheets from which the pad is fabricated bybeing simultaneously formed as shown in Fig. 3, and then separated for-removal of the edge portion of one of the sheets as shown in Fig. 4.Figs. 5 and `6 illustrate the attachment -to the outer and innersurfaces of these sheets of cooling fins and partition and reinforcingstrips. The hollow cooling pad shown in the drawing has twosubstantially parallel faces formed by the body portions of two sheetsIII and II, the edges of which have been turned up to form flanges I2and I3. These fianges are turned toward one another to space apart thebody portions of the sheets and are integrally attached to one anotherthroughout their lengths to form the edge walls of the pad, as well asthe side walls of two flared nipples I4 and I5 formed by projectionsarranged one within the other and extending fromthe edge of the pad. yThe configuration of the pad and the location of the nipples will dependon the use to which the pad is put. In the construction illustrated, thelower portion of the pad is divided by a slot I6, which formsfinger-like portions I l and I8 opposite the side from which the nipplesproject. This slot I6 is made to accommodate windings located in theslots of laminations forming the core structure of a dynamo-electricmachine and between 5 which laminations the pad is located.

Metal strips I 9 of substantially the same width as the width of theflanges of the sheets Ill and II are attached to the inner surfaces voi'the body portions of the sheets I0 and II. As shown in m Fig. 7, thesestrips are laterally spaced from one another with the outer strips I9spaced from the ends of the portions I'I and I8, and with theintermediate strip I9 spaced from the wall between the nipples I4 and I5to form a sinuous 15 passageway which extends between the openings inthe pad provided by the nipples. The ends I9a of these stripsareslightly spaced from the adjacent flanges of the sheet Il to slidablyreceive the fianges of the sheet I0. In the resulting 20 padconstruction the strips I9 are thus spaced from one another andalternately from opposite flanged portions of the sheets IIJ and Il toform the sinuous passageway referred to. Additional strips 20, havingthe same width as the strips. I9, 25 are also attached to the innersurfaces of the body portions of the sheets I0 and II and extend alongthe central portion of the passageway formed by the strips I9. 'I'heends of these additional strips are spaced from one vanother at 30points opposite the central portions of the strips I9 to provide for apressure equalization of the cooling-fluid flowing on opposite sides ofthese strips through the passageway defined by strips I9. Strips I9 and20 serve to reinforce the pad 35 against the compressive force exertedon its face portions in the assembled core structure of adynamo-electric machine. These strips also act as baiiles by means ofwhich the cooling fluid is directed in a predetermined path which bringsit 40 into intimate contact with the total surface portion of thecooling pad.

For some applications one of the external faces of the pad may beprovided with cooling fins 2i attached thereto in any desiredarrangement such 45 as illustrated in Fig. 1.

The structure of the pad will be further described in connection withthe procedure by means of which it is fabricated. This procedure formsthe subject matter of my above referred to 50 divisional application andis as follows:

Two metallic sheets I0 and I I are placed one upon the other in a pressby means of which their edge portions I2 and I9 are simultaneouslyturned up to form pans which closely fit one with- 56 sheet il. I 4inFig. 4, is removed from its turned up edge portion l2, to facilitate theassembly of these in the other, as shown in Fig. 3. The excess v metal22 at the rim of these pans is simultaneously removed from the turned upportions of the sheets to form flanges of substantially uniform width.The inner pan formed of sheet il is then separated from the outer panformed by Additional metal, above the line ifa sheets with their flangesturned toward and overlapping one another to form the hollow portion ofthe pad.

The sheets are then preferably cleaned by immersing them in hot water. acleaning solution, or a pickling bath, to remove o. and dirt therefrom,and the surfaces of the sheets where they are to be attached to oneanother and to the c strips II, 10 and 2i are preferably roughened bysuitable means such as steel grit directed thereon through the agency ofan air blast. Strips l! and 20 are then attached by welding them atintervals, as indicated at IIb and 20h, to the inner surface of the bodyportion of sheet Il, as

shown in Fig. 6. Strips 2| are then attached,

preferably by welding, to the outer surface of the body portion of thesheet III, as shown in Fig. 5. The turned up edges of the sheets III andIl and their surface areas, as well as vthe surface areas of the stripsI9, 20 and 2|, are then coated with a brazing material such as copper.which may be applied thereto as a molten metal spray. The parts are thenassembled as shown in Fig. 8 with the edge of .sheet Il turned over thebody portion of sheet I0 and the projections constituting the nipples i4and i5 formed around one another thus bring the edge portions of thesheets in close contact with one another. The assembly is then placed ina brazing furnace with the assembly resting on the outside surface ofthe body portion of the sheet. Il. Any suitable arrangement for applyinga pressure to the assembly may be placed in engagement with the ilns 2 iThe brazing operation is preferably performed in a hydrogen furnace toeffect that species of brazing known as hydrogen brazing. In thepresence of an atmosphere of hydrogen' the copper brazing materialreadily iiows into the crevices of the assembled parts and unites themone to the other in a manner closely approaching the condition of awelded union. The pad after the brazing operation is an integralstructure in which all the parts are ilrmly attached one to anotherthrough their contacting areas by the hydrogen brazing operation.

The nipples Il and I5 are flared to facilitate the attachment therein ofmetallic conduits, the

A ends of which can be soldered to the nipples by puddling the solder inthe annular space provided by their flared portions. I prefer to performsoldering operation by using a silver solder. melted by the flame of awelding torch in the presence of a fluxing material.

The metal of the pad structure may be of any suitable kind. but I preferto use for the sheets- Il and Ii and the strips Il and 2l, a coppernickel alloy known to the trade as Manel metal. I

usethismaterial becauseofitsresista'ncetocorrosion as well as its highelectrical resistance which prevents undue heating due to eddy currentlossesinthepadwhenusedaspart ofthe core structure of- 'a dynamo-electricmachine. Thenns 2| may be made of a low carbon steel dr any othersuitable material. These fins are provided to space the pad from anadjacent bundle of laminations and form eways for the circulation ofcooling gas between the pad and the bundle of laminations. These tins 2|may or may not form part of the pad structure. When used they also serveto conduct heat from the bundle of laminations placed in contacttherewith to the pad and to the cooling fluid circulated in the pad.

It is, of course. apparent that variations may be made in the structureof the pad, as well as in the procedure by means of which the pad isfabricated without departing from my invention. For example, the partsmay be attached to one another by welding. Furthermore, the flanged edgeportions of the sheets need not necessarily overlap one another, and maybe provided with rims for facilitating certain welding operations. It isalso apparent that the strips i9, 2li and 2| are not necessarilyattached throughout their lengths to the sheets Il and il, although suchconstruction strengthens the pad and facilitates the transfer of heatthrough the strips 2| to the body portion of the plate to which they areattached.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is:

l. A at hollow pad the faces of which are the body portions of twoparallel sheets having flanged edge portions turned toward one anotherand integrally attached to one another throughout their lengths to formthe edge walls of said pad, said flanged edge portions havingcooperating projections arranged one withinthe other to form a nipplecommunicating with the interior of said pad.

2. A flat hollow pad having strips therein attached to the innersurfaces of the faces of said pad and spaced from one another ndalternately from opposite edge walls of said pad to form a sinuouspassageway of non-uniformly varying cross-sectional area which occupiessubstantially all of the hollow portion of said pad and having attachedto the inner surfaces of the faces of said pad and extending along eachportion of Said passageway between said first-mentioned strips andbetween said first-mentioned strips and the edges of said pad adjacentthereto a plurality of aligned strips, the adjacent ends of which arespaced from one another at points opposite the central portions of saidfirst-mentioned strips and adjacent to points of material variation inthe cross-sectional area of said sinuous passageway.

MARION A. SAVAGE.

